This invention relates to a semiconductor device in which a monitor pattern for monitoring a variation in the patterning dimension of a resist film used for forming a semiconductor integrated circuit device (LSI device) and for monitoring a precise finish dimension of the LSI device is formed.
Further, this invention relates to a method for manufacturing the above semiconductor device.
A monitor pattern formed in a semiconductor device is used particularly for ensuring the precise finish dimension of an LSI device during a fine patterning process using lithography technology.
As is well known in the art of semiconductor device manufacturing processes, and in particular, in the fine patterning process using the lithography technology, it is known that even if the dimension of a resist film pattern used for forming elements in an LSI device defined by the mask is constant, some portions of the resist film pattern will be formed with different finish dimensions, for example, by the standing wave effect of light caused by a variation in the film thickness of a resist film due to a difference in level of the background layer, the microloading effect caused by a variation in the supply amount of an etchant due to a difference in the density of the mask pattern, or the proximity effect caused by a variation in the exposure light amount due to a variation in the density (dense or sparse arrangement) of the mask pattern.
That is, a variation occurs in the dimension of the resist film in principle by patterning.
However, conventionally, for example, a quality control (QC) or monitor pattern having a specified pattern dimension is formed on the scribe line of a wafer. Whether the pattern dimension of the monitor pattern is set within a specified range or not is determined by monitoring the dimension thereof so as to ensure the precise finish dimension of the LSI device even though a difference in level of the background layer randomly exists in the actual LSI device.
Therefore, with the conventional monitor pattern, a variation in the finish dimension of the entire portion of the LSI device cannot be monitored and the precise finish dimension of the LSI device cannot always be ensured.
Particularly, the dimension of the LSI device is finally determined by the finish dimension obtained after the etching process, but the difference between the dimension of the resist film pattern and the finish dimension, that is, the etching conversion difference is largely dependent on a difference in the density (dense or sparse arrangement) of the resist film pattern.
Therefore, the etching conversion difference determined by use of the conventional QC pattern formed with the specified pattern dimension cannot be applied to the entire portion of the resist film pattern in the LSI device, and strictly speaking, the precise finish dimension of the LSI device is not ensured at all in the prior art.
As described above, conventionally, a variation in the dimension of the resist film pattern in the actual LSI device cannot be monitored and there occurs a problem that the precise finish dimension of the LSI device is not always ensured.
This invention has been made in consideration of the above condition, and an object of this invention is to provide a semiconductor device having a monitor pattern with which variations in the dimensions of all of the element forming patterns in an actual semiconductor integrated circuit device can be monitored and in which the precise finish dimension of the semiconductor integrated circuit device can be more strictly ensured.
Further, an object of this invention is to provide a method for manufacturing the above semiconductor device.